Multi-speed transmission

ABSTRACT

A transmission of the present invention has an input member, an output member, four planetary gear sets, a plurality of coupling members and a plurality of torque transmitting devices. Each of the planetary gear sets includes first, second and third members. The torque transmitting devices may include clutches and brakes. The torque transmitting devices are selectively engageable in combinations of at least three to establish at least ten forward speed ratios and at least one reverse speed ratio

CROSS-REFFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.60/985,894 filed on Nov. 6, 2007. The disclosure of the aboveapplication is incorporated herein by reference.

FIELD

The invention relates generally to a multiple speed transmission havinga plurality of planetary gear sets and a plurality of torquetransmitting devices, and more particularly to a transmission having tenor more speeds, four planetary gear sets and a plurality of torquetransmitting devices.

BACKGROUND

The statements in this section merely provide background informationrelated to the present disclosure and may or may not constitute priorart.

A typical multiple speed transmission uses a combination of frictionclutches or brakes, planetary gear arrangements and fixedinterconnections to achieve a plurality of gear ratios. The number andphysical arrangement of the planetary gear sets, generally, are dictatedby packaging, cost and desired speed ratios.

While current transmissions achieve their intended purpose, the need fornew and improved transmission configurations which exhibit improvedperformance, especially from the standpoints of efficiency,responsiveness and smoothness and improved packaging, primarily reducedsize and weight, is essentially constant. Accordingly, there is a needfor an improved, cost-effective, compact multiple speed transmission.

SUMMARY

A transmission is provided having an input member, an output member,four planetary gear sets, a plurality of coupling members and aplurality of torque transmitting devices. Each of the planetary gearsets includes first, second and third members. The torque transmittingdevices are for example clutches and brakes.

In an aspect of the present invention a transmission is provided havingan input member, an output member, a first, second, third and fourthplanetary gear sets each having sun gears, carrier members and ringgears. The input member is continuously interconnected with at least oneof the sun gear of the first planetary gear set and the sun gear of thesecond planetary gear set. The output member is continuouslyinterconnected with the carrier member of the fourth planetary gear set.Additionally, a first interconnecting member continuously interconnectsthe sun gear of the first planetary gear set with the sun gear of thesecond planetary gear set, a second interconnecting member continuouslyinterconnects the ring gear of the first planetary gear set with thecarrier member of the second planetary gear set, a third interconnectingmember continuously interconnects the carrier member of the firstplanetary gear set with the ring gear of the fourth planetary gear set,a fourth interconnecting member continuously interconnects the ring gearof the second planetary gear set with the carrier member of the thirdplanetary gear set. Further, a first torque transmitting device isselectively engageable to interconnect the carrier member of the secondplanetary gear set with at least one of the sun gear of the secondplanetary gear set and the input member, a second torque transmittingdevice is selectively engageable to interconnect the carrier member ofthe fourth planetary gear set with the ring gear of the third planetarygear set, a third torque transmitting device is selectively engageableto interconnect the ring gear of the third planetary gear set with thesun gear of the fourth planetary gear set, a fourth torque transmittingdevice is selectively engageable to interconnect the carrier member ofthe second planetary gear set with the stationary member, a fifth torquetransmitting device is selectively engageable to interconnect the sungear of the third planetary gear set with the stationary member and asixth torque transmitting device is selectively engageable tointerconnect the sun gear of the fourth planetary gear set with thestationary member. The torque transmitting devices are selectivelyengageable in combinations of at least three to establish at least tenforward speed ratios and at least one reverse speed ratio between theinput member and the output member.

It is thus an object of the present invention to provide a transmissionhaving four planetary gear sets.

It is a further object of the present invention to provide atransmission having ten forward speeds and at least one reverse.

It is a still further object of the present invention to provide atransmission having four planetary gear sets, a plurality of couplingmembers and a plurality of torque transmitting devices.

Further objects, aspects and advantages of the present invention willbecome apparent by reference to the following description and appendeddrawings wherein like reference numbers refer to the same component,element or feature.

DRAWINGS

The drawings described herein are for illustration purposes only and arenot intended to limit the scope of the present disclosure in any way.

FIG. 1 is a lever diagram of an embodiment of a ten speed transmissionaccording to the present invention;

FIG. 2 is a diagrammatic view of an embodiment of a ten speedtransmission according to the present invention; and

FIG. 3 is a truth table presenting the state of engagement of thevarious torque transmitting elements in each of the available forwardand reverse speeds or gear ratios of the transmission illustrated inFIGS. 1 and 2.

DETAILED DESCRIPTION

The following description is merely exemplary in nature and is notintended to limit the present disclosure, application, or uses.

At the outset, it should be appreciated that in the particular exampleprovided, the ten speed automatic transmission of the present inventionhas an arrangement of permanent mechanical connections between theelements of the four planetary gear sets. A first component or elementof a first planetary gear set is permanently coupled to a firstcomponent or element of a second planetary gear set. A second componentor element of the first planetary gear set is permanently coupled to asecond component or element of the second planetary gear set. A thirdcomponent or element of a first planetary gear set is permanentlycoupled to a third component or element of a fourth planetary gear set.Finally, a third component or element of the second planetary gear setis permanently coupled to a third component or element of the thirdplanetary gear set.

Referring now to FIG. 1, an embodiment of a ten speed transmission 10 isillustrated in a lever diagram format. A lever diagram is a schematicrepresentation of the components of a mechanical device such as anautomatic transmission. Each individual lever represents a planetarygear set wherein the three basic mechanical components of the planetarygear set are each represented by a node. Therefore, a single levercontains three nodes: one for the sun gear, one for the planet gearcarrier, and one for the ring gear. The relative length between thenodes of each lever can be used to represent the ring-to-sun ratio ofeach respective gear set. These lever ratios, in turn, are used to varythe gear ratios of the transmission in order to achieve appropriateratios and ratio progression. Mechanical couplings or interconnectionsbetween the nodes of the various planetary gear sets are illustrated bythin, horizontal lines and torque transmitting devices such as clutchesand brakes are presented as interleaved fingers. If the device is abrake, one set of the fingers is grounded. Further explanation of theformat, purpose and use of lever diagrams can be found in SAE Paper810102, “The Lever Analogy: A New Tool in Transmission Analysis” byBenford and Leising which is hereby fully incorporated by reference.

The transmission 10 includes an input shaft or member 12, a firstplanetary gear set 14 having three nodes: a first node 14A, a secondnode 14B and a third node 14C, a second planetary gear set 16 havingthree nodes: a first node 16A, a second node 16B and a third node 16C, athird planetary gear set 18 having three nodes: a first node 18A, asecond node 18B and a third node 18C, a fourth planetary gear set 20having three nodes: a first node 20A, a second node 20B and a third node20C and an output shaft or member 22.

The input member 12 is coupled to the first node 14A of the firstplanetary gear set 14 and the first node 16A of the second planetarygear set 16. The output member 22 is coupled to the second node 20B ofthe fourth planetary gear set 20. The first node 14A of the firstplanetary gear set 14 is coupled to the first node 16A of the secondplanetary gear set 16. The second node 14B of the first planetary gearset 14 is coupled to the second node 16B of the second planetary gearset 16. The third node 14C of the first planetary gear set 14 is coupledto the third node 20C of the fourth planetary gear set 20. The thirdnode 16C of the second planetary gear set 16 is coupled to the thirdnode 18C of the third planetary gear set 18.

A first clutch 26 selectively connects the input member 12 with thesecond node 16B of the second planetary gear set 16. A second clutch 28selectively connects the second node 18B of the third planetary gear set18 with the second node 20B of the fourth planetary gear set 20. A thirdclutch 30 selectively connects the second node 18B of the thirdplanetary gear set 18 with the first node 20A of the fourth planetarygear set 20. A first brake 32 selectively connects the second node 16Bof the second planetary gear set 16 with a stationary element or thetransmission housing 50. A second brake 34 selectively connects thefirst node 18A of the third planetary gear set 18 with a stationaryelement or a transmission housing 50. A third brake 36 selectivelyconnects the first node 20A of the fourth planetary gear set 20 with astationary element or the transmission housing 50.

Referring now to FIG. 2, a stick diagram presents a schematic layout ofthe embodiment of the ten speed transmission 10 according to the presentinvention. In FIG. 2, the numbering from the lever diagram of FIG. 1 iscarried over. The clutches, brakes, and couplings are correspondinglypresented whereas the nodes of the planetary gear sets now appear ascomponents of planetary gear sets such as sun gears, ring gears, planetgears and planet gear carriers.

For example, the planetary gear set 14 includes a sun gear member 14A, aring gear member 14B, and a planet gear carrier member 14C thatrotatably supports a set of planet gears 14D (only one of which isshown). The planet gears 14D are each configured to intermesh with boththe sun gear member 14A and the ring gear member 14B. The sun gearmember 14A is connected for common rotation with a first shaft orintermediate member 42. The ring gear member 14B is connected for commonrotation with a second shaft or intermediate member 44. The planetcarrier member 14C is connected for common rotation with a third shaftor intermediate member 46.

The planetary gear set 16 includes a sun gear member 16A, a ring gearmember 16C, and a planet gear carrier member 16B that rotatably supportsa set of planet gears 16D (only one of which is shown). The planet gears16D are each configured to intermesh with both the sun gear member 16Aand the ring gear member 16C. The sun gear member 16A is connected forcommon rotation with the input shaft or member 12 and with a first shaftor intermediate member 42. The ring gear member 16C is connected forcommon rotation with a fourth shaft or intermediate member 48. Theplanet carrier member 16B is connected for common rotation with thesecond intermediate member 44 and with a fifth shaft or intermediatemember 52.

The planetary gear set 18 includes a sun gear member 18A, a ring gearmember 18B, and a planet gear carrier member 18C that rotatably supportsa set of planet gears 18D (only one of which is shown). The planet gears18D are each configured to intermesh with both the sun gear member 18Aand the ring gear member 18B. The sun gear member 18A is connected forcommon rotation with a sixth shaft or intermediate member 54. The ringgear member 18B is connected for common rotation with a seventh shaft orintermediate member 56. The planet carrier member 18C is connected forcommon rotation with the fourth shaft or intermediate member 48.

The planetary gear set 20 includes a sun gear member 20A, a ring gearmember 20C, and a planet gear carrier member 20B that rotatably supportsa first set of planet gears 20D (only one of which is shown) and asecond set of planet gears 20E (only one of which is shown). The firstset of planet gears 20D are each configured to intermesh with both thesun gear member 20A and the second set of planet gears 20E. The secondset of planet gears 20E are configured to intermesh with both the ringgear member 20C and the first set of planet gears 20D. The sun gearmember 20A is connected for common rotation with a ninth intermediatemember 60. The ring gear member 20C is connected for common rotationwith the third intermediate member 46. The planet carrier member 20B isconnected for common rotation with a tenth shaft or intermediate member62 and with output shaft or member 22.

The input shaft or member 12 is continuously connected to an engine (notshown) or to a turbine of a torque converter (not shown). The outputshaft or member 22 is continuously connected with the final drive unitor transfer case (not shown).

The torque-transmitting mechanisms or the clutches 26, 28, 30 and thebrakes 32, 34 and 36 allow for selective interconnection of the shaftsor intermediate members, members of the planetary gear sets and thehousing. For example, the first clutch 26 is selectively engageable toconnect the input member 12 with the fifth intermediate member 52. Thesecond clutch 28 is selectively engageable to connect the seventhintermediate shaft or member 56 with the tenth intermediate shaft ormember 62. The third clutch 30 is selectively engageable to connect theseventh intermediate shaft or member 56 with the ninth intermediateshaft or member 60. The first brake 32 is selectively engageable toconnect the fifth intermediate member 52 with a stationary element orthe transmission housing 50 in order to prevent the fifth intermediatemember 52 from rotating relative to the transmission housing 50. Thesecond brake 34 is selectively engageable to connect the sixthintermediate member 54 with a stationary element or the transmissionhousing 50 in order to prevent the sixth intermediate member 54 fromrotating relative to the transmission housing 50. The third brake 36 isselectively engageable to connect the ninth intermediate member 60 witha stationary element or the transmission housing 50 in order to preventthe ninth intermediate member 60 from rotating relative to thetransmission housing 50.

Referring now to FIGS. 2 and 3, the operation of the embodiment of theten speed transmission 10 will be described. It will be appreciated thatthe transmission 10 is capable of transmitting torque from the inputshaft or member 12 to the output shaft or member 22 in at least tenforward speed or torque ratios and at least one reverse speed or torqueratio with a triple overdrive. Each forward and reverse speed or torqueratio is attained by engagement of one or more of thetorque-transmitting mechanisms (i.e. first clutch 26, second clutch 28,third clutch 30, first brake 32, second brake 34 and third brake 36), aswill be explained below. FIG. 3 is a truth table presenting the variouscombinations of torque-transmitting elements that are activated orengaged to achieve the various gear states. Actual numerical gear ratiosof the various gear states are also presented although it should beappreciated that these numerical values are exemplary only and that theymay be adjusted over significant ranges to accommodate variousapplications and operational criteria of the transmission 10. An exampleof the gear ratios that may be obtained using the embodiments of thepresent invention are also shown in FIG. 3. Of course, other gear ratiosare achievable depending on the gear diameter, gear teeth count and gearconfiguration selected.

To establish reverse gear, the second clutch 28, the first brake 32 andthe second brake 34 are engaged or activated. The second clutch 28connects the seventh intermediate member 56 with the tenth intermediatemember 62. The first brake 32 connects the fifth intermediate member 52with a stationary element or the transmission housing 50 in order toprevent the fifth intermediate member 52 from rotating relative to thetransmission housing 50. The second brake 34 connects the sixthintermediate member 54 with a stationary element or the transmissionhousing 50 in order to prevent the sixth intermediate member 54 fromrotating relative to the transmission housing 50. Likewise, the tenforward ratios are achieved through different combinations of clutch andbrake engagement, as shown in FIG. 3. It will be appreciated that theforegoing explanation of operation and gear states of the ten speedtransmission 10 assumes, first of all, that all the clutches and brakesnot specifically referenced in a given gear state are inactive ordisengaged and, second of all, that during gear shifts, i.e., changes ofgear state, between at least adjacent gear states, a clutch or brakeengaged or activated in both gear states will remain engaged oractivated.

The description of the invention is merely exemplary in nature andvariations that do not depart from the gist of the invention areintended to be within the scope of the invention. Such variations arenot to be regarded as a departure from the spirit and scope of theinvention.

1. A transmission comprising: an input member; an output member; first,second, third and fourth planetary gear sets each having first, secondand third members; a first interconnecting member continuouslyinterconnecting the first member of the first planetary gear set withthe first member of the second planetary gear set; a secondinterconnecting member continuously interconnecting the second member ofthe first planetary gear set with the second member of the secondplanetary gear set; a third interconnecting member continuouslyinterconnecting the third member of the first planetary gear set withthe third member of the fourth planetary gear set; a fourthinterconnecting member continuously interconnecting the third member ofthe second planetary gear set with the third member of the thirdplanetary gear set; and six torque transmitting devices selectivelyengageable to interconnect one of the first, second, and third memberswith at least one other of the first members, second members, thirdmembers, and a stationary member, and wherein the torque transmittingdevices are selectively engageable in combinations of at least three toestablish at least ten forward speed ratios and at least one reversespeed ratio between the input member and the output member.
 2. Thetransmission of claim 1 wherein a first of the six torque transmittingdevices is selectively engageable to interconnect the second member ofthe second planetary gear set with at least one of the first member ofthe second planetary gear set and the input member.
 3. The transmissionof claim 2 wherein a second of the six torque transmitting devices isselectively engageable to interconnect the second member of the fourthplanetary gear set with the second member of the third planetary gearset.
 4. The transmission of claim 3 wherein a third of the six torquetransmitting devices is selectively engageable to interconnect thesecond member of the third planetary gear set with the first member ofthe fourth planetary gear set.
 5. The transmission of claim 4 wherein afourth of the six torque transmitting devices is selectively engageableto interconnect the second member of the second planetary gear set withthe stationary member.
 6. The transmission of claim 5 wherein a fifth ofthe six torque transmitting devices is selectively engageable tointerconnect the first member of the third planetary gear set with thestationary member.
 7. The transmission of claim 6 wherein a sixth of thesix torque transmitting devices is selectively engageable tointerconnect the first member of the fourth planetary gear set with thestationary member.
 8. The transmission of claim 1 wherein the firstmember of the first planetary gear set, the first member of the secondplanetary gear set, the first member of the third planetary gear set andthe first member of the fourth planetary gear set are sun gears, thethird member of the first planetary gear set, the second member of thesecond planetary gear set, the third member of the third planetary gearset and the second member of the fourth planetary gear set are carriermembers and the second member of the first planetary gear set, thirdmember of the second planetary gear set, the second member of the thirdplanetary gear set and the third member of the fourth planetary gear setare ring gears.
 9. The transmission of claim 1 wherein the input memberis continuously interconnected with at least one of the first member ofthe first planetary gear set and the first member of the secondplanetary gear set and wherein the output member is continuouslyinterconnected with the second member of the fourth planetary gear set.10. The transmission of claim 1 wherein three of the six torquetransmitting devices are brakes and three of the six torque transmittingdevices are clutches.
 11. The transmission of claim 1 wherein thestationary member is a transmission housing.
 12. A transmissioncomprising: an input member; an output member; first, second, third andfourth planetary gear sets each having first, second and third members,wherein the input member is continuously interconnected with at leastone of the first member of the first planetary gear set and the firstmember of the second planetary gear set and wherein the output member iscontinuously interconnected with the second member of the fourthplanetary gear set; a first interconnecting member continuouslyinterconnecting the first member of the first planetary gear set withthe first member of the second planetary gear set; a secondinterconnecting member continuously interconnecting the second member ofthe first planetary gear set with the second member of the secondplanetary gear set; a third interconnecting member continuouslyinterconnecting the third member of the first planetary gear set withthe third member of the fourth planetary gear set; a fourthinterconnecting member continuously interconnecting the third member ofthe second planetary gear set with the third member of the thirdplanetary gear set; and a first torque transmitting device selectivelyengageable to interconnect the second member of the second planetarygear set with at least one of the first member of the second planetarygear set and the input member; a second torque transmitting deviceselectively engageable to interconnect the second member of the fourthplanetary gear set with the second member of the third planetary gearset; a third torque transmitting device selectively engageable tointerconnect the second member of the third planetary gear set with thefirst member of the fourth planetary gear set; a fourth torquetransmitting device selectively engageable to interconnect the secondmember of the second planetary gear set with the stationary member; anda fifth torque transmitting device selectively engageable tointerconnect the first member of the third planetary gear set with thestationary member; a sixth torque transmitting device selectivelyengageable to interconnect the first member of the fourth planetary gearset with the stationary member; and wherein the torque transmittingdevices are selectively engageable in combinations of at least three toestablish at least ten forward speed ratios and at least one reversespeed ratio between the input member and the output member.
 13. Thetransmission of claim 12 wherein the first member of the first planetarygear set, the first member of the second planetary gear set, the firstmember of the third planetary gear set and the first member of thefourth planetary gear set are sun gears, the third member of the firstplanetary gear set, the second member of the second planetary gear set,the third member of the third planetary gear set and the second memberof the fourth planetary gear set are carrier members and the secondmember of the first planetary gear set, third member of the secondplanetary gear set, the second member of the third planetary gear setand the third member of the fourth planetary gear set are ring gears.14. The transmission of claim 12 wherein the stationary member is atransmission housing.
 15. A transmission comprising: an input member; anoutput member; first, second, third and fourth planetary gear sets eachhaving sun gears, carrier members and ring gears, wherein the inputmember is continuously interconnected with at least one of the sun gearof the first planetary gear set and the sun gear of the second planetarygear set and wherein the output member is continuously interconnectedwith the carrier member of the fourth planetary gear set; a firstinterconnecting member continuously interconnecting the sun gear of thefirst planetary gear set with the sun gear of the second planetary gearset; a second interconnecting member continuously interconnecting thering gear of the first planetary gear set with the carrier member of thesecond planetary gear set; a third interconnecting member continuouslyinterconnecting the carrier member of the first planetary gear set withthe ring gear of the fourth planetary gear set; a fourth interconnectingmember continuously interconnecting the ring gear of the secondplanetary gear set with the carrier member of the third planetary gearset; and a first torque transmitting device selectively engageable tointerconnect the carrier member of the second planetary gear set with atleast one of the sun gear of the second planetary gear set and the inputmember; a second torque transmitting device selectively engageable tointerconnect the carrier member of the fourth planetary gear set withthe ring gear of the third planetary gear set; a third torquetransmitting device selectively engageable to interconnect the ring gearof the third planetary gear set with the sun gear of the fourthplanetary gear set; a fourth torque transmitting device selectivelyengageable to interconnect the carrier member of the second planetarygear set with the stationary member; and a fifth torque transmittingdevice selectively engageable to interconnect the sun gear of the thirdplanetary gear set with the stationary member; a sixth torquetransmitting device selectively engageable to interconnect the sun gearof the fourth planetary gear set with the stationary member; and whereinthe torque transmitting devices are selectively engageable incombinations of at least three to establish at least ten forward speedratios and at least one reverse speed ratio between the input member andthe output member.
 16. The transmission of claim 15 wherein thestationary member is a transmission housing.